1. Field of the Invention
The invention relates to a circuit breaker, and more particularly to a circuit breaker with a time-delay function.
2. Description of the Related Art
Nowadays circuit breakers are widely used for protecting and controlling electrical power transmission networks. As shown in FIG. 1, a circuit breaker in the prior art comprises a firewire input end 032 and a firewire output end 037 connected to electric lines, an operating portion, comprising a lever 021 having an operating end disposed outside a housing 001 and operating to switch on or off a circuit, a first movable contact 024 having a first movable contact point 025 disposed on one end thereof, a linkage control block comprising multiple linkage parts 022 comprising multiple linkage parts and rotating with respect to a shaft in the housing 001, one end of an uppermost linkage part 0221 being connected to the lever 021, and one end of a downmost linkage part 0222 being connected to a front end 023 of the first movable contact, a static contact point 031 connected to the firewire input end 032. As the lever 021 rotates, the linkage control block 022 forces the first movable contact 024 to move, whereby implementing attachment and detachment between the first movable contact point 025 and the static contact point 031 and thus switch-on and switch-off of the electric lines. The circuit breaker further comprises an arc extinguishing portion and an over-current protecting portion 051. The arc extinguishing portion operates to prevent electric arc from damaging the circuit breaker, and comprises a metal plate 033 and an arc-extinguishing cover 035. The metal plate 033 is connected to the static contact point 031 and extends to the bottom of the housing 001. The arc-extinguishing cover 035 corresponds to the static contact point 031. The over-current protecting portion 051 is an electromagnetic release disposed below the operating portion. One end of the over-current protecting portion 051 is connected to the removable contact, and the other end thereof is connected to one end of the linkage part 052, and the other end of the linkage part 052 is connected to the linkage control block 022. As over current occurs on the electric lines, the first movable contact point is separated from the static contact point whereby disconnecting the loads from the electric lines.
However, there are several un-neglectable problems with the existing circuit breaker: firstly, the circuit breaker cannot be remotely controlled, if a load is to be disconnected from electric lines due to some reasons (such as owing money) via the circuit breaker, operators need to get to the site and solve the problem, which reduces operation efficiency; secondly, after long-term use, adhesion between the first movable contact point and the static contact point occurs, which reduces safety of the circuit breaker; thirdly, as power failure occurs, users cannot determine whether the circuit breaker fails and often blindly repair the circuit breaker, which reduces safety thereof; finally, if the circuit breaker fails, no clear indication is given to users, which makes it impossible to timely repair the circuit breaker and to normally use electricity.